The Mid Norwegian - NE Greenland conjugate margins: Rifting evolution, margin segmentation, and breakup

Abstract In this contribution we review our knowledge of the regional first order geometry of the Norwegian - Greenland Sea rift system, focusing on the evolution of the distal margins and on breakup. We include a description of selected published and unpublished geoseismic profiles considered as representative of the margins architecture, from the More - Jan Mayen conjugates to the Lofoten - North-East Greenland segment. The selected transects illustrate the geometry of the extensional system and outline the main structural units. Based on these transects, we discuss rifting evolution at the regional scale, focusing on along-strike architectural variability and on the relationship between the distal and outer margin domains and breakup. In that framework, we examine the definition of breakup, the lateral variations in terms of structures and magmatism, discuss the possible nature and role of transfer features, and the formation and isolation of microplates. We propose to consider the distal margin domains as segmented and multiphased basins, floored by exhumed altered crustal and/or mantle rocks, variously affected by magmatic additions in diverse forms, and capped by crustal allochthons of different dimensions. We favour the role of tectonic processes in the separation of the Jan Mayen microcontinent from the More and Voring margins. And, along the same line of thought, we propose that it was the lateral change of structural roles of large-magnitude fault complexes that became responsible for the along-strike segmentation of the margin.